New here and to 4x4. I've got a 99 lt 4dr with the 4 button 4wd. If i push auto 4wd, 4hi or 4low the light blinks then shuts off. The service 4wd light isn't on so im guessing a vacuum problem. The thing under the battery looks good and has no holes i can see. The actuator on the firewall is what i think is bad. It has vacuum going to it, but when i hit 4hi i can't feel vacuum coming out of it. Is that normal? Or does that mean its bad? Thanks for any help.

 

Do you hear any clicks in the dash?

 

Yes when i hit 4wd auto, 2hi, sometimes with 4hi. Now 4lo seem to work... but it keeps flashing when i hit 4lo. But i feel it go into a low gear and when i give it gas it seems to be in 4lo but it bucks a lil

 

you have to be in neutral to go into 4 lo

 

Ik. I put it in N then hit 4lo